System and Method for Adapting an Application Source Rate to a Load Condition

ABSTRACT

A system and method for adapting an application source rate to a load condition are provided. A method for forming a connection includes receiving a service authorization request for service between the first device and the second device, requesting a formation of a first bearer at a first data rate between the first device and the second device, and determining if the first bearer was formed. The method also includes transmitting a first positive response if the first bearer was formed, forming a second bearer at a second data rate if the first bearer was not formed, and completing the connection. The service authorization request includes a request to establish a connection at the first data rate, and the second data rate is different from the first data rate.

This application claims the benefit of U.S. Provisional Application No.61/187,654, filed on Jun. 16, 2009, entitled “Method and Apparatus forAdapting an Application Source Rate to a Load Condition in a WirelessCommunications Network,” which application is hereby incorporated hereinby reference.

TECHNICAL FIELD

The present invention relates generally to a system and method forwireless communications, and more particularly to a system and methodfor adapting an application source rate to a load condition.

BACKGROUND

Generally, in 4 G communications systems, such as Third GenerationPartnership Project (3GPP) Long Term Evolution (LTE) compliantcommunications systems, voice communications may be supported in theform of voice over Internet protocol (VoIP), wherein voice data istransmitted as a data packet. For example, a user equipment (UE), whichmay also be commonly referred to as a mobile station (MS), may use anadaptive multi-rate (AMR) speech coder and decoder (CODEC) to generate avoice frame containing voice data. The UE may subsequently add areal-time protocol (RTP) header, a user data protocol (UDP) header, andan Internet protocol (IP) header to the voice frame to form an IPpacket. The UE then transmits the IP packet over an air interface to anenhanced NodeB (eNB), which may also be referred to as a base station(BS).

The AMR CODEC is a single integrated speech CODEC with multiple sourcebit-rates ranging from a low of 4.75 kbps to a high of 12.2 kbps, and alow rate Silence Descriptor (SID) encoding mode for background noise.The AMR CODEC is capable of switching its bit-rate every 20-msec uponcommand.

In a 3GPP LTE compliant communications system, an eNB providestransportation for data and signalling between the UE and a corenetwork. The eNB also provides necessary control signalling to the UE inorder to maintain radio communications. The eNB may become overloadedwhen traffic load increases, such as during busy hours of operation. TheeNB may become overloaded with respect to its radio links, transportnetwork, and/or due to hardware and/or software limitations in networkequipment.

In order to alleviate the overload, the eNB may wish to reduce the datarate for UE communications. For example, the eNB may only grant new UEcommunications at low data rates, even if the granted data rates arelower than data rates requested by the UE. Furthermore, the eNB maycause existing UE communications to reduce their data rates.

SUMMARY OF THE INVENTION

These and other problems are generally solved or circumvented, andtechnical advantages are generally achieved, by preferred embodiments ofthe present invention which provides a system and method for adapting anapplication source rate to a load condition.

In accordance with a preferred embodiment of the present invention, amethod for forming a connection is provided. The method includesreceiving a service authorization request for service between a firstdevice and a second device, requesting a formation of a first bearer atthe first data rate between the first device and the second device,determining if the first bearer was formed, transmitting a firstpositive response if the first bearer was formed, forming a secondbearer at a second data rate between the first device and the seconddevice if the first bearer was not formed, and completing theconnection. The service authorization request includes a request toestablish a connection at a first data rate, and the second data rate isdifferent from the first data rate.

In accordance with another preferred embodiment of the presentinvention, a method for forming a connection including a communicationsdevice is provided. The method includes setting up a subscription forsignalling path information, receiving signalling path information uponan occurrence of a trigger event, determining acceptable serviceinformation based on the signalling path information, and completing theconnection based on the acceptable service information. The signallingpath originates or terminates at the communications device.

In accordance with another preferred embodiment of the presentinvention, a method for communications device operations is provided.The method includes receiving congestion information related to acommunications controller serving a communications device, processingthe received congestion information, requesting a formation of aconnection in response to determining that the communications device isto participate in the connection, and adjusting an active data rate ofan active connection to an adjusted data rate in response to determiningthat the communications device is participating in the activeconnection. The connection has a data rate based on the accumulatedcongestion information, and the active data rate is adjusted based onthe accumulated congestion information.

An advantage of an embodiment is that CODEC rate selection may be finetuned in response to available resources at connection setup so that aselected rate will not exceed available resources nor will the selectedrate be so far below an achievable rate due to an erroneously grantedrate request that communications performance may fall belowexpectations. Furthermore, fine control of CODEC quality versus loadconditions may be possible.

A further advantage of an embodiment is that a more rapid connectionsetup may be possible if a requested CODEC rate is not available andCODEC rate reduction is required, thereby improving user experience.

Yet another advantage of an embodiment is that fine tuning of CODEC rateduring connection operation is allowed, so if load conditions changewhile a connection is active, the CODEC rate may be changed (eitherincreased or decreased) to meet the changing load conditions.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the embodiments that follow may be better understood.Additional features and advantages of the embodiments will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiments disclosed may be readily utilized as a basisfor modifying or designing other structures or processes for carryingout the same purposes of the present invention. It should also berealized by those skilled in the art that such equivalent constructionsdo not depart from the spirit and scope of the invention as set forth inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawing, in which:

FIG. 1 is a diagram of network components in a communications system;

FIG. 2 is a flow diagram of operations in a prior art technique forresponding to a connection request requesting service at a specificCODEC rate;

FIG. 3 is a flow diagram of operations in establishing and responding toa connection request requesting service at a specific CODEC rate;

FIG. 4 is a diagram of a call flow in a connection setup, whereinadditional CODEC information is provided to a requester of theconnection in response to a rejection of a service authorizationrequest, and wherein a UE is an initiator of the connection being setup;

FIG. 5 a is a diagram of a call flow of a connection setup, wherein aPCRF intervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is an initiator of theconnection being setup;

FIG. 5 b is a diagram of a call flow of a connection setup, wherein aPCRF intervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is a terminator of theconnection being setup;

FIG. 6 a is a diagram of a call flow of a connection setup, wherein anAF intervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is an initiator of theconnection being setup;

FIG. 6 b is a diagram of a call flow of a connection setup, wherein anAF intervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is a terminator of theconnection being setup;

FIG. 7 is a diagram of a call flow in reactively providing acceptablebearer information;

FIG. 8 is a flow diagram of operations in setting up a connection withproactively provided communications system load information andacceptable bearer information;

FIG. 9 a is a diagram of a call exchange in the setup of a subscriptionfor a delivery of signalling path information;

FIG. 9 b is a diagram of a call exchange in a connection setup initiatedby a UE, wherein communications system load information and acceptablebearer information, as well as other signalling path information, areproactively provided;

FIG. 9 c is a diagram of a call exchange in a connection setupterminated by a UE, wherein communications system load information andacceptable bearer information, as well as other signalling pathinformation, are proactively provided;

FIG. 9 d is a diagram of a call exchange in an eNB providingcommunications system load information;

FIG. 10 is a flow diagram of operations in utilizing congestioninformation to determine CODEC rate;

FIG. 11 is a diagram of a CODEC rate adjustment transition diagram;

FIG. 12 a is a diagram of an AMR frame header;

FIG. 12 b is a diagram of available AMR CODEC rates; and

FIG. 13 is a diagram of a UE.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the presently preferred embodiments arediscussed in detail below. It should be appreciated, however, that thepresent invention provides many applicable inventive concepts that canbe embodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the invention, and do not limit the scope of the invention.

The present invention will be described with respect to preferredembodiments in a specific context, namely a 3GPP LTE compliantcommunications system. The invention may also be applied, however, toother communications systems, such as those that are 3GPP LTE-Advance,WiMAX, and so forth, compliant.

FIG. 1 illustrates network components in a communications system 100.Network components that may be involved in a connection between a UE 105and a far end device 110 are shown. The connection may have originatedat UE 105 and terminated at far end device 110 or originated at far enddevice 110 and terminated at UE 105.

Other network components involved in the connection include an eNB 115,a mobility management entity (MME)/serving gateway (SGW)/packet datanetwork gateway (PGW) 120, a policy control and charging rules function(PCRF) 125, and an application function (AF) 130.

As discussed previously, eNB 115 may be used to provide transportationof data and signalling to UE 105. In general, eNB 115 may be responsiblefor controlling incoming and outgoing transmissions to and from UE 105.MME/SGW/PGW 120 may be separate entities but may also be implemented asa single unit depending on communications system architecture. MME maybe used to initiate paging and authenticating of UE 105, as well asmaintaining location information of UE 105. SGW may be used to route andforward user data (usually in the form of packets) for UE 105. SGW mayalso be used as a mobility anchor during handovers. PGW may be used toprovide UE 105 connectivity to external packet data networks. PGW mayserve as a point of entry and exit of traffic to and from UE 105. PCRF125 may be used to detect service flow, enforce charging function, andso forth, in communications system 100. AF 130 may be used to providedynamic policy or charging control.

eNB 115, MME/SGW/PGW 120, PCRF 125, and AF 130 shown in FIG. 1 may beassociated with UE 105. To maintain simplicity, network componentsserving similar function to those shown in FIG. 1 but associated withfar end device 110 but are not shown.

FIG. 2 illustrates a flow diagram of operations 200 in a prior arttechnique for responding to a connection request requesting service at aspecific CODEC rate. Operations 200 may occur in a PCRF, for example.

Operations 200 may begin with the PCRF receiving a service authorizationrequest (block 205). The service authorization request may include aspecific CODEC rate. The PCRF may then request a bearer setup with thespecific CODEC rate for the bearer (block 210).

After requesting the bearer setup, the PCRF may perform a check todetermine if a response to the bearer setup request has been receivedand if it has, was the bearer setup request was accepted or rejected(block 215). If the bearer setup request was accepted, then the PCRF mayrespond to the service authorization request with an indication that theservice authorization request succeeded and continue with additionaloperations to complete a setup of the service (block 220). Operations200 may then terminate.

However, if the bearer setup request was rejected (block 215), then thePCRF may respond to the service authorization request with an indicationthat the service authorization request failed (block 225). In itsresponse to the service authorization request, the PCRF simply indicatesthat the service authorization request failed with no additionalinformation that may provide a reason why the service authorizationrequest failed or hint at an acceptable CODEC rate what would haveresulted in a successful service authorization request. It is then up tothe device that requested the service authorization, e.g., a UE, torespond to the failed service authentication request. Operations 200 maythen terminate.

As discussed above, the prior art technique illustrated in FIG. 2 doesnot provide any information that may assist a requester of service inestablishing a connection. Therefore, if the requester's serviceauthorization request is rejected, the requester is blind to what CODECrate would result in an accepted connection (if any). The requester maythen be forced to submit additional service authorization requests,which may take additional time as well as additional communicationssystem resources that may be scarce when the communications system is inan overloaded state.

FIG. 3 illustrates a flow diagram of operations 300 in establishing andresponding to a connection request requesting service at a specificCODEC rate. The flow diagram shown in FIG. 3 may illustrate a high levelview of an IP multimedia subsystem (IMS)-based technique forestablishing and responding to a connection request requesting serviceat a specific CODEC rate.

The flow diagram illustrates operations based on IMS signalling and mayinclude enhancements to protocols between an access network, a corenetwork, and IMS entities during connection setup. The IMS-basedtechniques provides solutions for CODEC rate selection and modificationby network components during connection setup that may or may not bebased on resource availability.

According to current LTE signalling, a bearer setup attempt may only beaccepted or rejected if insufficient resources are available to supportthe desired bearer configuration (e.g., QCI, GBR, etc.). Furthermore, acause for the rejection may be indicated in current LTE signalling.However, there is no information to be included that may indicate whatbearer configuration would be acceptable for acceptance, such as a lowerCODEC rate.

Operations 300 may be indicative of operations occurring in a PCRF asthe PCRF receives a service authorization request from a UE requesting aconnection with a specified CODEC rate. Operations 300 may occur whilethe PCRF is in a normal operating mode.

Operations 300 may begin with the PCRF receiving a service authorizationrequest (block 305). The service authorization request may be from an AFin response to a connection request from a UE. The service authorizationrequest may include a specific CODEC rate or multiple specific CODECrates. As an example, the service authorization request may containseveral acceptable CODEC rates with a highest CODEC rate being a mostpreferred.

The PCRF may then request a bearer setup with the specific CODEC ratefor the bearer (block 310). According to an embodiment, the request fora bearer setup may be sent to an MME/SGW/PGW anchoring a terminating UE,which may be forwarded to an eNB serving the terminating UE. The eNB maydetermine if it wishes to support communications at the specific CODECrate.

The PCRF may perform a check to determine if a response to the bearersetup request has been received and if it has, was the bearer setuprequest was accepted or rejected (block 315). If the bearer setuprequest was accepted, then the PCRF may respond to the serviceauthorization request with an indication that the service authorizationrequest succeeded (block 320) and continue with additional operations tocomplete a setup of the service (block 325). Operations 300 may thenterminate.

However, if the bearer setup request was rejected (block 315), then thePCRF may respond to the service authorization request by causing to forma bearer at a rate different from the specific CODEC rate (block 330).After forming the bearer at a different rate, the PCRF may continue tocomplete the service setup (block 325). In causing to form the bearer ata different rate, the PCRF may take several actions that are responsiveto the rejection of the service authorization request and may helpimprove the performance of the communications system.

In general, the PCRF (or another network entity, such as an AF) mayprovide additional information such as acceptable CODEC rates and/orconfiguration that may be accepted given communications system load.Alternatively, given acceptable bearer configuration and/or acceptableCODEC rates, the PCRF (or the AF) may be able to take steps to modifythe service authorization request accordingly.

According to an embodiment, the PCRF (or the AF) may provide in itsresponse to the service authorization request, information related toacceptable CODEC rates. As an example, if the service authorizationrequest specified a CODEC rate of A and was subsequently rejected, thePCRF may include acceptable CODEC rates of B, C, and D in its responseto the service authorization request, where CODEC rates B, C, and D aredifferent from CODEC rate A, and generally are lower rates than CODECrate A. The initiator of the service authorization request may theninitiate another service authorization request.

According to another embodiment, the PCRF (or the AF) may intervene withthe service authorization request and actively participate in theconnection setup. The PCRF (or the AF) may, upon determining that thebearer setup request was rejected, submit subsequent bearer setuprequests at different (typically lower) CODEC rates. Once the eNBaccepts a bearer setup request at a different CODEC rate, the PCRF (orthe AF) may respond to the service authorization request with anindication that the service authorization request was accepted but at aCODEC rate that is different from the specific CODEC rate.

Detailed discussions of the embodiments are provided below.

FIG. 4 illustrates a call flow in a connection setup, wherein additionalCODEC information is provided to a requester of the connection inresponse to a rejection of a service authorization request, and whereina UE is an initiator of the connection being setup. As shown in FIG. 4,the message exchange in the connection setup involves messages between aUE 405, an eNB 410, a MME/SGW/PGW 415, a PCRF 420, and an AF 425.

The call flow may begin with AF 425 sending a service authorizationrequest to PCRF 420 (block 430). Since UE 405 is the initiator of theconnection being setup, the service authorization request may haveoriginated from UE 405 with a terminator of the connection being setupbeing a far end device, such as another UE, a data source, or some otherfar end communications device. The service authorization request mayspecify a CODEC rate desired for the connection. PCRF 420 may then senda network bearer setup request to MME/SGW/PGW 415, which may serve toanchor UE 405 (block 432). The network bearer setup request may includeinformation regarding the bearer that PCRF 420 wishes to establish,including a desired CODEC rate.

MME/SGW/PGW 415, in response to the network bearer setup request, maysend a bearer setup request that includes the desired CODEC rate to eNB410, which is serving UE 405 (block 434). For discussion purposes, leteNB 410, according to its load, reject the bearer setup request (block436). According to an embodiment, rather than simply rejecting thebearer setup request, eNB 410 may provide information regarding therejected bearer setup request. As an example, eNB 410 may specify one ormore CODEC rates that it may find acceptable. Usually, the one or moreCODEC rates may be lower than the desired CODEC rate.

eNB 410 may send a bearer setup response along with the informationregarding the rejected bearer setup request (e.g., the one or moreacceptable CODEC rates) to MME/SGW/PGW 415 (block 438). MME/SGW/PGW 415may send a network bearer request response with the informationregarding the rejected bearer setup request to PCRF 420 (block 440).

PCRF 420 may then determine acceptable service information based on theone or more acceptable CODEC rates (block 442) and send a serviceauthorization response to AF 425 containing the acceptable serviceinformation (block 444). PCRF 420 select a CODEC rate from the one ormore acceptable CODEC rates based on historical information, its ownknowledge of communications system conditions, the specified CODEC ratefrom UE 405, expected use of the connection, and so forth, to beincluded in the acceptable service information.

AF 425 may send an IMS session rejection along with the acceptableservice information to UE 405, originator of the service authorizationrequest (block 446). Based on the acceptable service information, UE 405may initiate another service authorization request with a differentspecified CODEC rate (block 448). Alternatively, if the CODEC ratespecified in the acceptable service information is not acceptable to UE405, then UE 405 may elect to abandon trying to setup the connection andperhaps attempt to create the connection at a later time.

FIG. 5 a illustrates a call flow of a connection setup, wherein a PCRFintervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is an initiator of theconnection being setup. As shown in FIG. 5 a, the message exchange inthe connection setup involves messages between a UE 505, an AF 507, aPCRF 509, and an evolved packet core (EPC) 511.

The call flow may begin with UE 505 initiating a connection with aservice delivery platform (SDP) offer sent to AF 507 (block 515). AF 507may define downlink connection information which may include CODEC rate(block 517) and forward the SDP offer to far end network components(block 519). The far end network components may respond to the SDP offerwith a SDP answer (block 521).

Based on information contained in the SDP answer, AF 507 may be able todefine uplink connection information which may also include CODEC rate(block 523). AF 507 may then be ready to setup a bearer based to supportthe connection request from UE 505. AF 507 may send a DiameterAA-request (AAR) to PCRF 509 (block 525). According to an embodiment,the Diameter AAR may include information such as media-type, maximumrequested bandwidth (both uplink and downlink), codec data, and soforth.

PCRF 509 may store session information and identify an IP-CAN session(block 527) and send a Diameter re-auth-request (RAR) to EPC 511 (block529). The Diameter RAR may include information such as PCC rules,including Quality of Service Class Identifier (QCI),Allocation/Retention Priority (ARP), and so forth). EPC 511 may thendecide to grant the Diameter RAR based on considerations such asavailable resources, for example.

For discussion purposes, assume that EPC 511 fails the Diameter RAR. EPC511 informs PCRF 509 of the failure of the Diameter RAR by using aDiameter re-auth-answer (RAA) (block 533). PCRF 509 informs AF 507 ofthe failure of the Diameter AAR with a Diameter AA-answer (AAA)indicating a rejection (block 535). AF 507 (or a proxy CSCF) may modifythe CODEC rate to a lower bandwidth, for example (block 537) and AF 507may send a new Diameter AAR with the new CODEC rate to PCRF 509 (block539).

PCRF 509 may then send a new Diameter RAR with the new CODEC rate to EPC511 (block 541). For discussion purposes, let EPC 511 grant a newDiameter RAR with the new CODEC rate. EPC 511 sends a new Diameter RAAwith an indication of success of the Diameter RAR to PCRF 509 (block543) and PCRF 509 sends a new Diameter AAA with an indication of successof the Diameter AAR with an indication of acceptance to AF 507 (block545). AF 507 sends a SDP answer to UE 505 with an indicator of amodified CODEC rate (block 547).

FIG. 5 b illustrates a call flow of a connection setup, wherein a PCRFintervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is a terminator of theconnection being setup. The call flow of the connection setup as shownin FIG. 5 b is substantially similar to the call flow shown in FIG. 5 awith exception of an ordering of the definition of the uplink anddownlink connection information (the uplink and the downlink connectioninformation definition are reversed) and the SDP offer and SDP answeroriginate and terminate with far end network components rather than theUE.

As shown in FIGS. 5 a and 5 b, no IMS session re-attempts are made by UE505 (or the far end network component originating the connectionrequest). Furthermore, PCRF 509 may accept or reject the SDP informationprovided by UE 605 (or the far end network component originating theconnection request) but may not modify information contained within theSDP offer.

FIG. 6 a illustrates a call flow of a connection setup, wherein an AFintervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is an initiator of theconnection being setup. As shown in FIG. 6 a, the message exchange inthe connection setup involves messages between a UE 605, an AF 607, aPCRF 609, and an evolved packet core (EPC) 611.

The call flow may begin with UE 605 initiating a connection with a SDPoffer sent to AF 607 (block 615). AF 607 may define downlink connectioninformation which may include CODEC rate (block 617) and forward the SDPoffer to far end network components (block 619). The far end networkcomponents may respond to the SDP offer with a SDP answer (block 621).

Based on information contained in the SDP answer, AF 607 may be able todefine uplink connection information which may also include CODEC rate(block 623). AF 607 may then be ready to setup a bearer based to supportthe connection request from UE 605. AF 607 may send a DiameterAA-request (AAR) to PCRF 609 (block 625). According to an embodiment,the Diameter AAR may include information such as media-type, maximumrequested bandwidth (both uplink and downlink), codec data, and soforth.

PCRF 609 may store session information and identify an IP-CAN session(block 627) and send a Diameter re-auth-request (RAR) to EPC 611 (block629). The Diameter RAR may include information such as PCC rules,including QCI, ARP, and so forth). EPC 611 may then decide to grant theDiameter RAR based on considerations such as available resources, forexample.

For discussion purposes, assume that EPC 611 fails the Diameter RAR. EPC611 informs PCRF 609 of the failure of the Diameter RAR by using aDiameter re-auth-answer (RAA) (block 633). According to an embodiment,included in the Diameter RAA may be information related to availableresources, e.g., a maximum available bandwidth.

PCRF 609 may modify the specified CODEC rate or select a new CODEC ratebased on the information related to the available resources provided inthe Diameter RAA from EPC 611 (block 635) and send a new Diameter RARwith the modified or new CODEC rate to EPC 611, thereby requesting a newbearer with the modified specified CODEC rate or new CODEC rate (block637).

Let EPC 611 grant the new bearer request and create the bearer (block639) and sends a new Diameter RAA to PCRF 609 with an indication ofsuccess (block 641). PCRF 609 may send a new Diameter AAA with anindication of acceptance of Diameter AAR with the modified or new CODECrate to AF 607 (block 643). AF 607 may send a SDP answer to UE 605indicating that the connection request by UE 605 has been granted but atthe modified or new CODEC rate (block 645).

FIG. 6 b illustrates a call flow of a connection setup, wherein an AFintervenes in the connection setup in response to a rejection of aservice authorization request, and wherein a UE is a terminator of theconnection being setup. The call flow of the connection setup as shownin FIG. 6 b is substantially similar to the call flow shown in FIG. 6 awith exception of an ordering of the definition of the uplink anddownlink connection information (the uplink and the downlink connectioninformation definition are reversed) and the SDP offer and SDP answeroriginate and terminate with far end network components rather than theUE.

As shown in FIGS. 6 a and 6 b, no IMS session re-attempts are made by UE605 (or the far end network component originating the connectionrequest). Furthermore, PCRF 609 may modify the SDP information providedby UE 605 (or the far end network component originating the connectionrequest).

Communications system load information, along with acceptable bearerconfiguration may be communicated to the PCRF (or PGW) in severaldifferent ways. According to an embodiment, a reactive approach may beused to communicate communications system load information andacceptable bearer information to the PCRF (or PGW). In the reactiveapproach, the acceptable bearer information (and communications systemload information) may be provided by the eNB only in response to aconnection setup request and when the connection setup request cannot befulfilled, i.e., the connection setup request is rejected by the eNB. Anadvantage of the reactive approach is that signalling load may beminimized at the expense of increased bearer setup delay.

FIG. 7 illustrates a call flow in reactively providing acceptable bearerinformation. As shown in FIG. 7, a MME/SGW/PGW sends a connection setuprequest, for example, an E-RAB setup request, to an eNB controlling a UEinitiating a connection request (block 705). The eNB may send back tothe MME/SGW/PGW a response, for example, an E-RAB setup response, withone or more acceptable bearer configurations (block 710). TheMME/SGW/PGW may send to a PCRF the one or more acceptable bearerconfigurations (block 715) and the PCRF may determine that at least oneof the one or more acceptable bearer configurations are met (block 720).

The MME/SGW/PGW may then send a connection setup request, for example,another R-RAB setup request, to the eNB, wherein the connection setuprequest contains an indication that the one or more acceptable bearerconfigurations are met (block 725). The UE and the eNB may coordinate toreconfigure the connection (block 730) and the eNB may send a connectionsetup response to the MME/SGW/PGW with an indication that the bearer hasbeen setup (block 735).

According to an embodiment, a proactive approach may be used tocommunicate communications system load information and acceptable bearerinformation to the PCRF (or PGW). In the proactive approach, the eNBprovides a congestion report to the PCRF (or PGW) once a default beareris established. The congestion report may be updated and/or maintainedeither periodically or trigger by events, such as changing loadconditions or connection status. An advantage of the proactive approachis that communications system load information may be immediatelyavailable to the PCRF (or PGW) at time of bearer creation, therebyminimizing delays in bearer setup since the communications system loadinformation may be used to select an appropriate CODEC rate a first timea connection setup is attempted with no rejections, retries, and soforth.

FIG. 8 illustrates a flow diagram of operations 800 in setting up aconnection with proactively provided communications system loadinformation and acceptable bearer information. Operations 800 may beindicative of operations occurring in network components, such as an AFor a PCRF, involved in setting up a connection to or from a UE.Operations 800 may occur while the communications system is in a normaloperating mode.

Operations 800 may begin with an establishment of a subscription for thedelivery of signalling path status, such as communications system loadinformation, acceptable bearer information, congestion information, andso forth (block 805). According to an embodiment, an AF may subscribe toreceive from a PCRF notifications regarding signaling path status. Thesubscription may utilize existing signalling capabilities of thecommunications system and may be triggered by session initiationprotocol (SIP) registration with the IMS network. With the subscriptionsetup, the AF may periodically receive from the PCRF signalling pathstatus updates. Alternatively, the AF may receive the signalling pathstatus updates from the PCRF whenever a signalling path status changes,such as when a connection from a UE changes from idle to busy and viceversa.

At predetermined times or occurrence of an event, the PCRF may sendsignalling path information to the AF (block 810). The AF may make useto the signalling path information to determine acceptable serviceinformation (block 815). As an example, the AF may determine anacceptable CODEC rate based on the signalling path information.

The AF may then respond to a service authorization request based on theacceptable service information (block 820). For example, if the serviceauthorization request includes a specified CODEC rate that is higherthan what is included in the acceptable service information, the AF mayreject the service authorization request and suggest an acceptable CODECrate or the AF may reject the service authorization request andintervene in the service authorization request process and initiate itsown service request at acceptable CODEC rates. Operations 800 may thenterminate.

FIG. 9 a illustrates a call exchange in the setup of a subscription fora delivery of signalling path information. As shown in FIG. 9 a, thecall exchange involves a UE 905, an eNB 907, a PGW 909, a PCRF 911, andan AF 913.

The call exchange may begin with UE 905 registering with acommunications system through a SIP registration message with the AF 913as UE 905 enters the communications system (block 915). AF 913 may wishto receive updates regarding signalling path information related to UE905.

AF 913 receives signalling path information updates by establishing asubscription with PGW 909 which anchors UE 905. Establishing thesubscription may be achieved by sending a subscription to notificationof signalling path information to PCRF 911 (block 917), which in turn,sends a congestion registration notification message to PGW 909 (block919).

PGW 909 saves in its memory a congestion event involving UE 905 and AF913 so that whenever a signalling path status related to UE 905 changes,PGW 909 may send the signalling path status change to AF 913 (block921). According to an embodiment, certain signalling path status changeswill result in PGW 909 sending the signalling path information change toAF 913. For example, when the status of a connection involving UE 905changes from idle to busy may be a trigger for PGW 909 to sendsignalling path information to AF 913. PGW 909 may then send acongestion registration notification response to PCRF 911 to indicatethat the subscription has been successfully recorded (block 923).

FIG. 9 b illustrates a call exchange in a connection setup initiated bya UE, wherein communications system load information and acceptablebearer information, as well as other signalling path information, areproactively provided. As shown in FIG. 9 b, the call exchange involves aUE 955, an eNB 957, a PGW 959, a PCRF 961, and an AF 963.

The call exchange may begin with UE 955 participating in a connectionsetup procedure with eNB 957 (block 965). In order to participate in theconnection setup procedure, UE may first register with thecommunications system. Discussion of UE registration procedures may bebeyond the scope of the embodiments and will not be discussed herein.

As a result of UE 955 registering with the communications system, AF 963may wish to receive updates regarding signalling path informationrelated to UE 955. AF 963 may receive updates by subscribing for thedelivery of signalling path information updates. AF 963 may subscribefor the delivery of signalling path information updates by participatingin a call exchange such as on shown in FIG. 9 a.

After participating in the connection setup procedure with UE 955, eNB957 may participate in a default bearer setup procedure with PGW 959(block 967). In addition to participating in the default bearer setupprocedure with PGW 959, eNB 957 may send signalling path information toPGW 959, wherein the signalling path information may reflect changes dueto the setup of the default bearer.

The setup of the default bearer may be a triggering event for thedelivery of signalling path information (block 971). As a result of theoccurrence of the triggering event, PGW 959 may send signalling pathinformation, including communications system congestion report to PCRF961 (block 973). PCRF 961 may maintain an accumulation of signallingpath information. Alternatively, PCRF 961 maintains only a most recentcopy of the signalling path information.

UE 955 may initiate a setup of a connection with a far end networkcomponent through an SIP invite message to AF 963 (block 975). Inresponse to which, AF 963 may send a service authorization request toPCRF 961 with a specific CODEC rate as specified in the SIP invitemessage from UE 955 (block 977). According to the signalling pathinformation, e.g., communications system load information, stored atPCRF 961, PCRF 961 may determine acceptable service information, whichmay or may not be equal to the specific CODEC rate specified by UE 955or AF 963 (block 979).

PCRF 961 may send a response to the service authorization request,wherein the response includes the acceptable service information (block981). For discussion purposes, assume that the PCRF determines that thespecific CODEC rate as specified in the SIP invite is not acceptable andreject the SIP invite, AF 963 may send a message with an indication of arejection along with the acceptable service information to UE 955 (block983). Based on the acceptable service information included in themessage from AF 963, UE 955 may decide to setup another connection usingthe acceptable service information (block 985) or abandon the attempt tosetup the connection all together or try again at a later time.

FIG. 9 c illustrates a call exchange in a connection setup terminated bya UE, wherein communications system load information and acceptablebearer information, as well as other signalling path information, areproactively provided. The call exchange shown in FIG. 9 c may besubstantially similar to the call exchange shown in FIG. 9 c in that amulti-step process is followed, including a setup of a subscription forsignalling path status updates, detection of a triggering event to sharethe signalling path information, determining acceptable serviceinformation from the signalling path information, and accepting orrejecting a connection request based on the acceptable serviceinformation.

FIG. 9 d illustrates a call exchange in an eNB providing communicationssystem load information. The call exchange shown in FIG. 9 d illustratesthe providing of communications system load information by the eNB to aPGW and then the PGW providing the communications system loadinformation in response to an occurrence of a triggering event.

FIG. 10 illustrates a flow diagram of operations 1000 in utilizingcongestion information to determine CODEC rate. The flow diagram shownin FIG. 10 may illustrate a radio access network (RAN)-based techniquefor utilizing congestion information to determine CODEC rate for setupof a connection and/or adjusting CODEC rate in an active connection.Operations 1000 may be indicative of operations occurring in a UE of acommunications system.

The RAN-based technique may enable fast response to changes incommunications load conditions. Additionally, rate adjustments may beperformed in an active connection, e.g. in the middle of the voice call,an audio/video conference, or so forth. The RAN-based technique allowsfor an eNB to broadcast its load conditions to UEs served by the eNB,and the UEs may accumulate the load conditions to get an estimate of eNBload conditions. Furthermore, a probabilistic approach to CODEC rateselection based on eNB load conditions may occur during connection setupor during an active connection.

Operations 1000 may begin with the UE receiving cell congestioninformation, such as in the form of a congestion indication, from an eNBserving the UE (block 1005). According to an embodiment, the cellcongestion information may be in the form of uplink cell congestioninformation, downlink cell congestion information, or both. The cellcongestion information may be transmitted by the eNB periodically or maybe triggered by specified thresholds, such as load thresholds.

The UE may observe and accumulate the cell congestion information (block1010). According to an embodiment, the accumulation of the cellcongestion information may occur over an observation window.

The UE may perform a check to determine if the UE is in an activeconnection (block 1015). If the UE is not in an active connection, thenthe UE may perform a check to determine if the UE wishes to setup aconnection (block 1020). If the UE does not wish to setup a connection,then the UE may return to block 1005 to receive additional cellcongestion information.

If the UE does wish to setup a connection, then the UE may request aconnection with a CODEC rate determined based on the accumulated cellcongestion information (block 1025). According to an embodiment, the UEmay also select a CODEC rate based on connection type. A detaileddiscussion of the selection of the CODEC rate is provided below. Aftersetup of the connection with the CODEC rate, the UE may return to block1005 to receive additional cell congestion information.

If the UE is in an active connection, the UE may then perform a check todetermine if there is a need to adjust a service rate of the connection(block 1030). According to an embodiment, there may be a need to reducethe service rate of the connection if the CODEC rate of the connectionexceeds the acceptable service information, an error rate of theconnection exceeds an error threshold, a retry rate of the connectionexceeds a retry threshold, a negative acknowledgement rate exceeds anegative acknowledgement threshold, or so forth. Alternatively, theremay be a need to increase the service rate of the connection if acurrent CODEC rate is less than the acceptable service information,performance of the connect is below accepted standards, utilization ofthe communications system is below utilization threshold, desired CODECrates provided by participants of the connection, or so on.

If the UE determines that there is a need to adjust the service rate ofthe connection (block 1030), then the UE may adjust the service ratebased on the accumulated congestion information and the current CODECrate of the connection (block 1035). After adjusting the service rate ofthe connection, the UE may return to block 1005 to receive additionalcell congestion information.

FIG. 11 illustrates a CODEC rate adjustment transition diagram. Thetransition diagram shown in FIG. 11 may be used for transitions betweenfour different CODEC rates: rate 1, rate 2, rate 3, and rate 4, withrate 1<rate 2<rate 3<rate 4. As an example, if a connection is at acurrent rate, rate 2, then the connection may be adjusted up to rate 3if the accumulated cell congestion information indicates that the eNB isnot loaded. Similarly, the connection may be adjusted down to rate 1 ifthe accumulated cell congestion information indicates that the eNB isloaded.

In order to help prevent a situation wherein all UEs served by the eNBadjusts their connections at the same time, a probabilistic approach maybe employed, wherein a UE may adjust the rate of its connection only ifa certain transition probability is met. For example, if the eNB is notloaded, a connection may have its rate adjusted from rate 2 up to rate 3with transition probability prob_23, which also means there is aprobability of (1−prob_23) that the connection will stay at rate 2.Similarly, if the eNB is loaded, a connection may have its rate adjustedfrom rate 2 down to rate 1 with transition probability prob_21, whichalso means there is a probability of (1−prob_21) that the connectionwill stay at rate 2. According to an embodiment, different transitionprobabilities may be used for up transitions and for down transitions.Similarly, different transition probabilities may be used for differentup transitions or different down transitions.

Optimization of the transition probabilities may be important. Thetransition probabilities may be standardized or configurable byinfrastructure equipment. AMR supports many different CODEC rates,therefore a number of possible combinations of rate transitions may bevery large. Therefore, optimization of different transitionprobabilities for an exhaustive list of every possible rate transitionmay be tedious and may consume a considerable amount of storage space.Therefore, it may be possible to limit rate transitions to neighboringCODEC rates, i.e., transition probabilities may be optimized only forCODEC rates immediately above and below each possible CODEC rate.

Furthermore, a transition probability may be set so that it is also afunction of a counter value of a number of cell congestion informationreceived or a function of accumulated cell congestion information, i.e.,a single cell congestion information indicating that the cell is loadedmay cancel out a single cell congestion information indicating that thecell is not loaded. The counter value may be maintained over a period oftime so that a persistent overload condition may induce a quicker rateadjustment from a UE. The counter value may be reset whenever a rateadjustment occurs.

The transition probabilities may also be a function of thecommunications system geometry (using averaged channel qualityindicator, for example) that a UE observes so that an eNB serving the UEmay maximize bandwidth savings, for example, for poor-geometry UEs,i.e., UEs with poor geometry may have a tendency to use a lower CODECrate.

Rate adjustments may be prohibited entirely or may be limited once theCODEC rate exceeds a CODEC rate initially negotiated during connectionsetup. Limiting or prohibiting rate adjustments may be accomplished bysetting appropriate transition probabilities to zero.

Assuming that a rate adjustment results in the CODEC rate being greaterthan a CODEC rate initially negotiated, there may be no need to changethe UE's evolved packet system (EPS) bearer so that the CODEC rate mayadapt quickly to RAN conditions during a connection without timeconsuming EPS negotiations. If rate adjustments are allowed, the UEknows the CODEC rate negotiate at initial call setup and may set a limitfor rate adjustments.

According to an embodiment, within an active connection, the UE maycontinue to monitor the eNB's cell congestion information and elect toadjust the CODEC rate (or connection source rate) up or down based onthe cell congestion information. FIG. 12 a illustrates an AMR frameheader 1200. In the AMR frame header 1200, there may be two fields thatmay be used in CODEC rate adjustment. A first field 1205 (CODEC modeindication (CMI)) may be used as an indication of the CODEC rate in adirection of transmission (uplink or downlink) and may be used to signalto peer network components in the connection, e.g., UEs, of a change inthe CODEC rate. A second field 1210 (CODEC mode request (CMR)) may beused to request a CODEC rate change in a direction opposite oftransmission with peer network components in the connection. FIG. 12 billustrates available AMR CODEC rates.

As discussed previously, rate adjustments may occur in both the downlinkand the uplink. In downlink rate adjustment, for rate reductions, the UEmay determine a desired downlink CODEC rate based on downlink cellcongestion information, a set of rates supported by peers of theconnection, a set of rate transition probabilities, and so forth. The UEmay forward the desired downlink rate in the CMR field of an uplink AMRframe header. A CODEC encoder at the far end of the connection receivesand then complies with the CMR field. The CODEC encoder may begin tosend packets using the new rate, with the packets containing a new CMIvalue corresponding to the CODEC rate.

If semi-persistent assignments are used on the uplink, then the UE atthe far end of the connection may insert padding bits in its uplinkpacket data unit (PDU) in order to fit the new payloads (smaller if theCODEC rate has been decreased) in the semi-persistent assignments. Inaddition to padding with padding bits, the UE at the far end of theconnection may insert padding buffer status reports (BSR). Then, an eNBof the UE at the far end of the connection may monitor the number ofpadding bits or padding BSRs. If the notices a consistent use and numberof padding bits/padding BSRs, then the eNB may subsequently reduce thesemi-persistent assignments.

If the semi-persistent assignments are used on the downlink of a nearside of the connection, then an eNB of the UE of the near side of theconnection may monitor a gap between downlink data units (SDU) and atransport block size assigned to the semi-persistent assignments and mayadjust the semi-persistent assignments as needed.

In uplink rate adjustment, for rate reductions, the UE may determine adesired uplink CODEC rate based on its current CODEC rate, cellcongestion information, a set of rates supported by peers of theconnection, a set of rate transition probabilities, and so forth.

If semi-persistent assignments are used on the uplink of the near end ofthe connection, the UE may transmit at the adjusted CODEC rate usingpreviously assigned semi-persistent assignment transport blocks andresource size. The UE may indicate the adjusted CODEC rate in the CMIfield in the AMR frame header. The UE may or may not insert padding BSRsin the PDU. If needed, the UE may insert padding bits. An eNB servingthe UE at the near end of the connection may monitor the number ofpadding bits (including the padding BSRs if present) in the PDU andadjusts the semi-persistent assignment transport blocks and resourceassignments by a packet data control channel if needed.

If the semi-persistent assignments are used on the downlink of the farend of the connection, then an eNB serving the UE at the far end of theconnection may monitor a gap between downlink SDU size andsemi-persistent assignment transport size previously assigned toassociated semi-persistent assignments and adjusts the semi-persistentassignment transport blocks and resource size as needed.

In both uplink and downlink rate adjustments, if the CODEC rate isincreased, the eNBs serving the UEs may monitor buffer utilization andif a consistent increase in buffer utilization is noticed, the eNBs mayadjust the semi-persistent assignment transport blocks and resource sizeas needed.

FIG. 13 illustrates a UE 1300. UE 1300 be used by a user to communicatewith other users and/or information sources. UE 1300 may be served by aneNB. UE 1300 may include a processor 1305 that may be used to runapplications and programs. Furthermore, processor 1305 may be used toprocess congestion information from the eNB serving UE 1300. As anexample, UE 1300 may accumulate the congestion information over anobservation window of time, wherein UE 1300 may simply add up thecongestion information to arrive at the accumulated congestioninformation.

Processor 1305 may also be used adjust a data rate of an activeconnection in which UE 1300 is participating. The adjusting of the datarate of the active connection may be based on the accumulated congestioninformation as well as transition probabilities. A discussion of aprobability based adjusting of the data rate was described previously.Processor 305 may make use of a random number generator to generate arandom number for use in adjusting the data rate of an activeconnection.

Processor 1305 may also be used to determine a data rate for aconnection request. The determining of the data rate for the connectionrequest may also be based on the accumulated congestion information.Furthermore, UE 1300 may also make use of transition probabilities todetermine the data rate for the connection request.

UE 1300 also includes a transmitter/receiver (TX/RX) 1310 that may beused to transmit and/or receive information over an antenna 1315. UE1300 also includes a memory 1320 that may be used to store information,such as the accumulated congestion information, the transitionprobabilities, random numbers, and so forth.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

1. A method for forming a connection, the method comprising: receiving aservice authorization request for service between a first device and asecond device, wherein the service authorization request comprises arequest to establish a connection at a first data rate; requesting aformation of a first bearer at the first data rate between the firstdevice and the second device; determining if the first bearer wasformed; transmitting a first positive response if the first bearer wasformed; forming a second bearer at a second data rate between the firstdevice and the second device if the first bearer was not formed, whereinthe second data rate is different from the first data rate; andcompleting the connection.
 2. The method of claim 1, wherein the seconddata rate is based on communications system load.
 3. The method of claim2, wherein the second data rate is less than the first data rate.
 4. Themethod of claim 1, wherein forming the bearer at a second data ratecomprises transmitting a negative response, wherein the negativeresponse comprises the second data rate.
 5. The method of claim 1,wherein forming the bearer at a second data rate comprises: requesting aformation of the second bearer between the first device and the seconddevice; determining if the second bearer was formed; transmitting asecond positive response if the second bearer was formed; and forming athird bearer at a third data rate between the first device and thesecond device if the second bearer was not formed, wherein the thirddata rate is different from second data rate and the first data rate. 6.The method of claim 5, wherein requesting a formation of the secondbearer, the determining if the second bearer was formed, thetransmitting a second positive response, and the forming a third bearerat a third data rate occurs at an applications function of acommunications system.
 7. The method of claim 5, wherein requesting aformation of the second bearer, the determining if the second bearer wasformed, the transmitting a second positive response, and the forming athird bearer at a third data rate occurs at policy and charging rulesfunction of a communications system.
 8. A method for forming aconnection including a communications device, the method comprising:setting up a subscription for signalling path information, wherein thesignalling path originates or terminates at the communications device;receiving signalling path information upon an occurrence of a triggerevent; determining acceptable service information based on thesignalling path information; and completing the connection based on theacceptable service information.
 9. The method of claim 8, whereinsetting up a subscription comprises: sending a request for subscriptionto notification of signalling path status to an anchor of thecommunications device; and receiving a response.
 10. The method of claim9, wherein the request includes a specification of the trigger event.11. The method of claim 8, wherein setting a subscription occurs duringan initial connection setup for the communications device.
 12. Themethod of claim 8, wherein determining acceptable service informationcomprises determining an acceptable data rate for the connection. 13.The method of claim 12, wherein determining an acceptable data ratecomprises finding a highest supportable data rate based on thesignalling path information.
 14. The method of claim 8, wherein thesignalling path information comprises cell load information.
 15. Amethod for communications device operations, the method comprising:receiving congestion information related to a communications controllerserving a communications device; processing the received congestioninformation; requesting a formation of a connection in response todetermining that the communications device is to participate in theconnection, wherein the connection has a data rate based on theaccumulated congestion information; and adjusting an active data rate ofan active connection to an adjusted data rate in response to determiningthat the communications device is participating in the activeconnection, wherein the active data rate is adjusted based on theaccumulated congestion information.
 16. The method of claim 15, whereinthe congestion information is broadcast to communications devices servedby the communications controller periodically or upon an occurrence ofan event.
 17. The method of claim 15, wherein processing the receivedcongestion information comprises accumulating the received congestioninformation.
 18. The method of claim 17, wherein the accumulating occursover an accumulation window.
 19. The method of claim 15, wherein theadjusting an active data rate occurs with a probability associated witha transition between the active data rate of the active connection andto the adjusted data rate.
 20. The method of claim 19, wherein theadjusted data rate is less than or equal to an initial data rate of theactive connection at formation of the active connection.